mlxsw: spectrum: Change signature of FID leave function

When a vPort is destroyed, it leaves the FID it's currently mapped to
(if any) and drops the reference. The FID's leave function expects to
get the vPort as its argument, but this will have to change when the
vPort model is retired.

Change the function signature to expect a Port-VLAN struct instead and
patch the call sites accordingly.

The code introduced in this patch will be removed later in the patchset,
but this intermediary step is required in order to ease the code review.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>